Apparatus and method for power management of a system of indicator light devices

ABSTRACT

Indicator light devices are useful in many applications for indicating properties of physical spaces respectively associated therewith and in physical proximity thereto. The indicator light devices are network-enabled and self-powered, and capable of participating in coordinated power-managed operation to provide a sufficient service life and lower installation and replacement costs. The indicator light devices may be used with or without associated sensors. The various embodiments described herein use various power management techniques singly or in combination to greatly increase the service life of self-power indicator light devices without diminishing their effectiveness in the application. These techniques include operating only the indicator light devices associated with the physical spaces having properties of interest, operating the indicator light devices with synchronized flashing, operating the indicator light devices in accordance with the detection of specific conditions, relevant time operation, in-vicinity activation, and ambient light responsiveness.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and is a continuation of U.S.patent application Ser. No. 13/100,230, entitled “Apparatus and Methodfor Power Management of a System of Indicator Light Devices,” filed May03, 2011 by Robert T. Fayfield, et al., the entire disclosure of whichis incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to indicator light devices, and moreparticularly to power management of a system of indicator light devices.

2. Description of Related Art

Indicator lights are used in a variety of different types of systems forindicating a condition existing in a physical space associated with andin physical proximity to the indicator light. Indicator lights arecommonly employed, for example, in smart parking systems. Smart parkingsystems have become popular in Asia, Europe and most recently in theUnited States. These systems are typically used in enclosed parkingstructures such as parking ramps to maximize parking utilization andincrease revenue for the operator (a ramp operator, for example), and toimprove the user's (a retail customer, for example) experience. One typeof smart parking system uses a vehicle sensor and an indicator,typically an LED light, in proximity to each parking spot to directcustomers to specific available parking spaces. A continuous green lighttypically indicates “available” while a continuous red light typicallyindicates “occupied.” An example of such a smart parking system whichuses a wireless network is disclosed in US Patent ApplicationPublication No. 2007/0050240 published Mar. 1, 2007 in the name ofBelani et al.

Other examples of systems that employ indicator lights are the picksystems and the pick-put systems common in warehouses and manufacturingfacilities. An example of a pick-put system is disclosed in U.S. Pat.No. 6,775,588 issued Aug. 10, 2004 to Peck. In this system, each of thevarious storage bays in a storage facility include a pick controller andintelligent light assemblies for each location on the bay, and a cartincludes a put controller and intelligent light assemblies adjacent tospecific receptacles located on the cart. A portable computer on thecart translates warehouse locations to light addresses of locations on astorage bay for indicating to the user (a worker, for example) the needfor and quantity of an item to be retrieved from the illuminatedlocation, and communicating instructions to intelligent light assembliesadjacent to specific receptacles located on the cart to indicate to theuser the quantity of the retrieved item to be deposited into aparticular one of the receptacles on the cart.

BRIEF SUMMARY OF THE INVENTION

For facilities using indicator lights in which the indicator lights andother system components are networked, the cost of installing networkcabling can be significant. While wireless components help avoid thecost and disruption of installing network cables throughout a facility,many systems that use indicator lights are still hard-wired to powersources because of power requirements. While many components of a systemdraw power, the indicator lights typically draw the most power, and thehard-wired connection to a power source is needed to provide sufficientpower for a sufficient duration as required in some applications.Unfortunately, having to connect the indicator lights to a power sourceincreases installation cost and limits installation options, and evenprecludes their use in some facilities. While the indicator lights andother components may be powered by batteries, this alternative is notentirely satisfactory for some applications because the power requiredby an indicator light can exhaust a battery in an impractically shorttime. These problems singly or in combination are solved by at leastsome of the embodiments of the present invention, which may also beapplicable to other problems.

One embodiment of the present invention is a method of operating aplurality of indicator light devices physically associated withrespective physical locations in a facility and networked over awireless network for indicating a condition of interest or a pluralityof conditions of interest at the physical locations in a manner viewableby a user of the facility. The method comprises identifying a firstsubset of the physical locations having a first condition of interest, afirst subset of the indicator light devices being physically associatedwith the first subset of physical locations; and operating the firstsubset of indicator light devices to provide a visual indication of thefirst subset of physical locations to the user. The operating stepcomprises synchronously flashing the indicator light devices in thefirst subset of indicator light devices in accordance withsynchronization information conveyed over the wireless network tovisually indicate the first subset of physical locations to the user.

Another embodiment of the present invention is a system comprising awireless network; a plurality of indicator light devices physicallyassociated with respective physical locations in a facility forindicating a condition of interest or a plurality of conditions ofinterest at the physical locations in a manner viewable by a user of thefacility, the indicator light devices being networked over the network;and a synchronization controller networked to the indicator lightdevices over the network for providing synchronization information to afirst subset of the indicator light devices to synchronously flash thefirst subset of the indicator light devices, the first subset of theindicator light devices being physically associated with a first subsetof the physical locations having the condition or conditions of interestto visually indicate the first subset of physical locations to the user.

Another embodiment of the present invention is an indicator light devicefor use on a wireless network in a facility along with a plurality ofnetworked indicator light devices physically associated with respectivephysical locations in a facility for indicating a condition of interestor a plurality of conditions of interest at the physical locations in amanner viewable by a user of the facility. The indicator light devicecomprises a light source for providing the visual indication; a wirelesscommunications node for connecting to the wireless network; a controllerfor controlling the light source and the wireless communications node;and a computer-readable medium accessible to the controller. Thecomputer-readable medium comprises controller-executable programinstructions for identifying a first subset of the physical locationshaving a first condition of interest, a first subset of the indicatorlight devices being physically associated with the first subset ofphysical locations; and providing synchronization information to thefirst subset of the indicator light devices to synchronously flash thefirst subset of the indicator light devices and visually indicate thefirst subset of physical locations to the user.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block schematic diagram of an indicator light device.

FIG. 2 is a block schematic diagram of an indicator light sensor device.

FIG. 3 is a block schematic diagram of a sensor device.

FIG. 4 is a block schematic diagram of an illustrative arrangement of anindicator light, sensor, communications and self-power source for anindicator light device.

FIG. 5 is a block schematic diagram of an illustrative arrangement of anindicator light, sensor, communications and self-power source for anindicator light device.

FIG. 6 is a block schematic diagram of an illustrative arrangement of anindicator light, sensor, communications and self-power source for anindicator light device.

FIG. 7 is a block schematic diagram of an illustrative arrangement of anindicator light, sensor, communications and self-power source for anindicator light device.

FIG. 8 is a block schematic diagram of an illustrative arrangement of anindicator light, sensor, communications and self-power source for anindicator light device.

FIG. 9 is a block schematic diagram of an illustrative arrangement of anindicator light, sensor, communications and self-power source for anindicator light device.

FIG. 10 is a block schematic diagram of an illustrative arrangement ofan indicator light, sensor, communications and self-power source for anindicator light device.

FIG. 11 is a block schematic diagram of an illustrative arrangement ofan indicator light, sensor, communications and self-power source for anindicator light device.

FIG. 12 is a block schematic diagram of an illustrative arrangement ofan indicator light, sensor, communications and self-power source for anindicator light device.

FIG. 13 is a block schematic diagram of an illustrative arrangement ofan indicator light, sensor, communications and self-power source for anindicator light device.

FIG. 14 is a block schematic diagram of an illustrative arrangement ofan indicator light, sensor, communications and self-power source for anindicator light device.

FIG. 15 is a block schematic diagram of an illustrative arrangement ofan indicator light, sensor, communications and self-power source for anindicator light device.

FIG. 16 is a block schematic diagram of an illustrative arrangement ofan indicator light, sensor, communications and self-power source for anindicator light device.

FIG. 17 is a block schematic diagram of an illustrative networkarrangement of indicator light devices.

FIG. 18 is a block schematic diagram of an illustrative networkarrangement of indicator light devices.

FIG. 19 is a block schematic diagram of an illustrative networkarrangement of indicator light devices.

FIG. 20 is a block schematic diagram of an illustrative networkarrangement of indicator light devices.

FIG. 21 is a block schematic diagram illustration various illustrativepower management functions for a network of indicator light devices.

FIG. 22 is a side plan diagram of an illustrative indicator lightdevice.

FIG. 23 is a side plan diagram of an illustrative indicator lightdevice.

FIG. 24 is a partial block schematic diagram, partial circuit diagram ofan illustrative indicator light device.

FIG. 25 is a pictorial view of a parking garage application which uses anetwork of indicator light devices.

DETAILED DESCRIPTION OF THE INVENTION, INCLUDING THE BEST MODE

Indicator light devices are useful in many applications for indicatingproperties of physical spaces respectively associated with and inphysical proximity to the indicator lights. Examples of suchapplications include parking garages, parking lots, on-street parking,warehouse pick systems and pick-put systems, and so forth. While notprecluding wired installations, the indicator light devices describedherein are network-enabled and self-powered, and capable ofparticipating in coordinated power-managed operation, so that indicatorsystems using them may be as effective as wired systems while having asufficient service life and lower installation and replacement costs.LED-based indicator lights are particularly useful because of theirrelatively low power requirements and long service life, although anytype of light source may be used. Other indicators such as sound sources(horns, voice messages, and the like) may be used along with theindicator light. Coordinated operation of the indicator light devicesmay be achieved in any desired manner, although the use of wirelessnetworking is particularly effective for minimizing installation andreplacement costs. The self-power source may be a power pack usingprimary (non-rechargeable) batteries, although other self-power sourceswhich may be suitable for some applications include power packs ofrechargeable batteries, small fuel cells, super capacitors, solar cells,and other such limited-power sources. The indicator light devices may beused with or without associated sensors, although the use of associatedsensors is advantageous in certain applications. Suitable sensorsinclude ultrasonic, photoelectric and video using, for example, patternrecognition. The autonomous power source may be integrated within thesame housing as the indicator light device, although it may be containedwithin a separate housing and locally wired to the indicator lightdevice. One or more sensors suitable for the intended application may beintegrated within the same housing as the indicator light device,although such sensors may be contained within a separate housing orhousings and locally wired to the indicator light device or wirelesslynetworked. The networking circuit may be integrated within the samehousing as the indicator light device, although it may be containedwithin a separate housing and locally wired to the indicator lightdevice.

Taking advantage of the networked nature of indicator light devices andparticular characteristics of certain applications, the variousembodiments described herein use various power management techniquessingly or in combination to greatly increase the service life ofself-power indicator light devices without diminishing theireffectiveness in the application. This makes self-powered indicatorlight devices practical and cost-effective for many applications. Thesetechniques include operating the indicator light devices withsynchronized flashing, specifying conditions of interest from amongvarious possible conditions of the physical spaces and operating onlythe indicator light devices associated with the physical spaces havingthe conditions of interest, operating the indicator light devices onlyduring relevant times, operating the indicator light devices based onsupply and demand, operating the indicator light devices based onpresence of the user, and adjusting respective intensities of theindicator light devices based on ambient light.

An indicator light system may include conventionally-powered indicatorlight devices along with self-powered indicator light devices.Advantageously, a self-powered indicator light device may include thecapability of being powered from a conventional power line, along withthe capability of detecting the power source and operating eitherwithout power management, or in accordance with some or all of the powermanagement techniques in order to provide a consistent experience to theuser.

Devices

FIG. 1 is a simplified block diagram of an illustrative indicator lightdevice 10. The indicator light device 10 includes communications 11 forcommunicating power management information and other data as desiredwith other indicator light devices, a gateway, a host, or anycombination thereof, either using wired or wireless communications orboth via any desired type of network, including, for example, activenetwork architectures, client-server network architectures, wireless adhoc network architectures, and peer-to-peer network architectures. Theindicator light device 10 also includes a light source 12 for providinga visual indication. Suitable light sources include unitary lightemitting devices as well as sources formed from arrays or otherarrangements of light emitting elements. The power management functionsand operation of the light source 12 are controlled by a controller 13.Many different types of devices and circuits may be used as thecontroller 13, including programmable controllers andmicroprocessor-memory subsystems which use executable program code,logic circuits, state machines, and any combination thereof. Wherememory is used, many different types of memory devices and circuits maybe used, including volatile, non-volatile, and combinations thereof.Power for the various elements of the indicator light device 10 isprovided by self-power source 14. The entire device 10 may be containedwithin one housing for maximum ease in installation. Alternatively, thedevice 10 may be implemented as interconnected modules for flexibilityand installation ease; for example, the self-power source 14 may beimplemented as a power module, the light source 12 may be implemented asan indicator module, and the controller 13 and communications 11 may beimplemented as a communications module, so that an installer may selecta desired type of indicator module and a desired type or capacity ofself-power source module for assembly into a single unit. Alternatively,the device 10 may be implemented as separate units; for example, theself-power source 14 may be implemented as a power unit in one housing,and the communications 11, the light source 12, and the controller 13may be implemented as an indicator unit in another housing so that aninstaller may mount the indicator unit in one location and theself-power source unit in another and perhaps less noticeable locationseparated from but near the indicator unit. The self-power source unitmay supply power to the indicator unit in any desired manner, includingby wire and inductively. Alternatively, the self-power source 14 may beimplemented as a power unit in one housing, the light source 12 may beimplemented as an indicator unit in one housing, and communications 11may be implemented as a communications unit in one housing, with thecontroller 13 being placed in any of the units as desired.Alternatively, each unit may be provided with its own power source. Thedevice 10 may be implemented in other permutations as well.

FIG. 2 is a simplified block diagram of a particular implementation ofthe indicator light device of FIG. 1, which includes a wireless datatransceiver 21 and associated antenna 27 for wireless communications, alight emitting diode (“LED”) 29 and LED driver 22 as a light source, anda sensor interface 25 and a sensor 28, illustratively an ultrasonicsensor of a type that is particularly useful in smart parking systemsfor sensing the presence or absence of a parked vehicle. The term lightemitting diode includes devices having one LED element as well asdevices having many arrayed or otherwise arranged LED elements. Thecontroller 23 is similar to the controller 13 of the indicator lightdevice 10 (FIG. 1) but is modified also to operate the sensor 28. Theentire device 20 may be contained within one housing, or implemented asinterconnected modules or as individual units or in any combinationthereof. Illustratively, the sensor interface 25 and sensor 28 may beimplemented as a sensor module and interconnected with another module orother modules to form the device 20. Illustratively, the sensorinterface 25 and sensor 28 may be implemented as a sensor unit in itsown housing, the LED 29 and LED driver 22 may be implemented as anindicator unit in its own housing, the wireless data transceiver 21 andassociated antenna 27 may be implemented as a communications unit in itsown housing, and the self-power source 14 may be implemented as a powerunit in one housing, with the controller 23 being in any of the units oreven being in its own housing. If desired, each unit may be providedwith its own self-power source. For applications in which the sensormust be located in a location that is not readily visible, the lightemitting diode (“LED”) 29 and LED driver 22, the wireless datatransceiver 21 and associated antenna 27, the controller 23, and theself-power source 14 may be implemented in a main unit, and sensor 28and sensor interface 25 may be implemented in a sensor unit. The device20 may be implemented in other permutations as well, including, forexample, separate indicator and sensor units provided with their ownpower and communications for combining placement flexibility withinstallation ease.

An example of a wirelessly networked sensor device 30 is shown in FIG.3. The sensor device 30 is similar to the indicator light device 20(FIG. 2), except that it lacks an indicator light. The controller 33 issimilar to the controller 23 except that it need not be capable ofcontrolling an indicator light source.

Some of the many permutations for implementing an indicator light deviceare shown in FIG. 4 through FIG. 14. In these figures, “I” representsindicator light, “S” represents sensor, “C” represents communications,and “P” represents a self-power source. A network node is shown forexternal communications, wherein the network may be, for example, awired network such as Ethernet, a wireless network such as Wi-Fi, or aproprietary wireless network. A proprietary wireless network thatemphasizes power efficiency using such techniques as reducing packetsize and time synchronization to minimize time on-air is particularlyadvantageous. However, any desired technology may be used for externalcommunications, including local area networks, wide area networks,personal area networks such as Bluetooth, peer-to-peer wirelesscommunications, and dedicated control and data line wiredcommunications. An indicator light device may include any one or more ofthese technologies. Controllers are not shown in these figures since acontroller or controllers may be contained in one unit, distributedacross multiple units, or replicated in multiple units, either with anindicator light, or sensor, or communications, or self-power source, orany combination thereof, or in its own unit, as desired.

FIG. 4 shows ISCP unit 40 in which an indicator light, sensor,communications, and power are integrated into a single unit.Communications is maintained via network node 41.

FIG. 5 shows an ICP unit 50 which integrates an indicator light,communications and power, and a SCP unit 55 with integrates a sensor,communications and power. ICP unit 50 includes network node 51, and SCPunit 55 includes network node 56, for communications between the unitsand to another one or more units, one or more gateways, a host, or anycombination thereof on the network.

FIG. 6 shows an ICP unit 60 which integrates an indicator light,communications and power, and a SP unit 65 which integrates a sensor andpower. ICP unit 60 includes network node 61 for communications toanother one or more units, one or more gateways, a host, or anycombination thereof on the network. Control signals between the ICP unit60 and the SP unit 65 are handled via respective control ports 62 and66.

FIG. 7 shows an ICP unit 70 which integrates an indicator light,communications and power, and a SP unit 75 which integrates a sensor andpower. ICP unit 70 includes network node 71 for communications toanother one or more units, one or more gateways, a host, or anycombination thereof on the network. Control signals between the ICP unit70 and the SP unit 75 are handled via respective control and power ports72 and 76, which may also be used if desired to share power between theunits 70 and 75. Power sharing may be done in any desired manner,ranging for example from full-time power sharing by having theself-power sources of the units 70 and 75 wired together, to peak loadleveling by selectively interconnecting the self-power sources of theunits 70 and 75 when one of the units experiences a peak load(illustratively the unit 70 when the indicator light must operate atmaximum intensity as in a bright light situation), to backup when theself-power source in one of the units 70 and 75 is exhausted.

FIG. 8 shows an IP unit 80 which integrates an indicator light andpower, and a SCP unit 85 which integrates a sensor, communications andpower. SCP unit 85 includes network node 86 for communications toanother one or more units, one or more gateways, a host, or anycombination thereof on the network. Control signals between the IP unit80 and the SCP unit 85 are handled via respective control ports 81 and87. If desired, control and power ports may be used instead of controlports 81 and 87, so that power may be shared between the units 80 and85.

FIG. 9 shows an ICP unit 90 which integrates an indicator light,communications and power, and a S unit 95 which only contains a sensor.ICP unit 90 includes network node 91 for communications to another oneor more units, one or more gateways, a host, or any combination thereofon the network. Control signals between the ICP unit 80 and the S unit85 are handled via respective control and power ports 92 and 96, whichare also used to provide power from the ICP unit 90 to the S unit 95.

FIG. 10 shows an I unit 100 which only contains an indicator light, andSCP unit 105 which integrates a sensor, communications and power. SCPunit 105 includes network node 106 for communications to another one ormore units, one or more gateways, a host, or any combination thereof onthe network. Control signals between the I unit 100 and the SCP unit 105are handled via respective control and power ports 101 and 107, whichare also used to provide power from the SCP unit 105 to the I unit 100.

FIG. 11 shows an I unit 110 which only contains an indicator light, Sunit 116 which only contains a sensor, and CP unit 112 which integratescommunications and power. CP unit 112 includes network node 113 forcommunications to another one or more units, one or more gateways, ahost, or any combination thereof on the network. Control signals betweenthe I unit 110, the CP unit 112, and the S unit 116 are handled viarespective control and power ports 111, 114 and 117, which are also usedto provide power from the CP unit 112 to the I unit 110 and the S unit116.

FIG. 12 shows an IS unit 120 which integrates an indicator light andsensor, and CP unit 122 which integrates communications and power. CPunit 122 includes network node 123 for communications to another one ormore units, one or more gateways, a host, or any combination thereof onthe network. Control signals between the IS unit 120 and the CP unit 122are handled via respective control and power ports 121 and 124, whichare also used to provide power from the CP unit 122 to the IS unit 120.

FIG. 13 shows an IC unit 130 which integrates an indicator light andcommunications, an S unit 136 which only contains a sensor, and P unit134 which only contains power. The IC unit 130 includes network node 131for communications to another one or more units, one or more gateways, ahost, or any combination thereof on the network. Control signals betweenthe IC unit 130 and the S unit 136 are handled via respective controland power ports 132 and 137. Power is provided from the power port 135of the P unit 134 to the power ports 132 and 137 of the IC unit 130 andthe S unit 136 respectively.

FIG. 14 shows an ISC unit 140 which integrates an indicator light,sensor and communications, and P unit 144 which contains only power. ISCunit 140 includes network node 141 for communications to another one ormore units, one or more gateways, a host, or any combination thereof onthe network. Power is provided by the P unit 144 to the ISC unit 140 viarespective power ports 145 and 142.

FIG. 15 shows an I unit 150 which contains an indicator light, a P unit152 which contains power, a C unit 154 which contains communications,and a S unit 158 which contains a sensor. The C unit 154 includesnetwork node 155 for communications to another one or more units, one ormore gateways, a host, or any combination thereof on the network.Control signals between the I unit 150, the C unit 154, and the S unit158 are handled via respective control and power ports 151, 156 and 159.Power is provided from the power port 153 of the P unit 152 to thecontrol and power ports 151, 156 and 159.

FIG. 16 shows an IC unit 162 which contains an indicator light andcommunications, a P unit 160 which contains power for the IC unit 162, aSC unit 165 which contains a sensor and communications, and a P unit 168which contains power for the SC unit 165. The IC unit 162 includesnetwork node 163 for communications to another one or more units, one ormore gateways, a host, or any combination thereof on the network. The SCunit 165 includes network node 166 for communications to another one ormore units, one or more gateways, a host, or any combination thereof onthe network. Control signals between the IC unit 162 and the SC unit 165are handled via respective control and power ports 164 and 167. Power isprovided to the IC unit 162 from the power port 161 of the P unit 160 tothe control and power port 164. Power is provided to the SC unit 165from the power port 169 of the P unit 168 to the control and power port167. If desired, power from the P unit 160 and the P unit 168 may beshared by the IC unit 162 and the SC unit 165 via the control and powerport 164 and the control and power port 167.

Networks

The indicator light devices in a system may be interconnected in anydesired manner, including dedicated control and data lines and wirelessand wired networks. Where networking is used, many suitable networktopologies are available, including, for example, bus, star, ring, tree,mesh, and fully connected or hybrid. Suitable network protocols forthese and other network topologies are well known in the art. Thenetwork may include different types of devices such as, for example,such device types as gateway devices, node devices, host computers,server computers, client devices, master devices, and slave devices inany combination of two or more.

A few examples of suitable network organizations are shown in FIG. 17through FIG. 20. The connecting lines between the various blocks areintended to show only how the network is organized, and are not intendedto show any particular network topology or protocol, or whether thenetwork is wired or wireless. While the networked devices shown are ISCPdevices which include an indicator light, sensor, communications andpower, these devices may be implemented in any desired manner (forexample, as a single unit (modular or unitary) or as multiple units).Moreover, other types of devices may be present on the network,including, for example, ICP devices which have an indicator light but nosensor, and SCP devices with have a sensor but no indicator light.Moreover, the network may also include line-powered devices.

FIG. 17 shows a simple network in which ISCP devices 171, 172 and 173are networked to a master 170 and are configured as slave devices. Themaster 170 alternatively may be a gateway, host, or client, with theISCP devices 171, 172 and 173 being nodes. The master 170 may be housedseparately from the ISCP devices 171, 172 and 173, or may be mountedwithin one of the ISCP devices 171, 172 and 173. This type of networkorganization is suitable, for example, for a facility in which alllocations are clustered together. It may be desirable for the master 170to be line-powered in those implementations in which the master 170 isfrequently active and provides relatively high power communications.

FIG. 18 shows a network in which gateway devices 185, 190 and 195 arenetworked to a host 180. ISCP devices 186, 187 and 188 are networked tothe gateway 185, ISCP devices 191, 192 and 193 are networked to thegateway 190, and ISCP devices 196, 197 and 198 are networked to thegateway 195. This type of network organization is suitable, for example,for a facility in which the locations are clustered into spatiallyseparated areas.

FIG. 19 shows a network in which client devices 210, 220, 230 andoptionally 240 are networked to a server 200. ISCP devices 211, 212 and213 are networked to the client 210, ISCP devices 221, 222 and 223 arenetworked to the client 220, and ISCP devices 231, 232 and 233 arenetworked to the client 230. An operator may manage the system from aseparate client device 240, illustratively an appropriately configuredpersonal computer. In this case, the clients 210, 220 and 230 may besimple and inexpensive specialized devices for exchanging informationbetween the various networked ISCP devices and the server.Alternatively, any one or more of the clients 210, 220 and 230 may be amore powerful device that is appropriately configured not only to forexchanging information between the various networked ISCP devices andthe server, but also to manage the system. This type of networkorganization is suitable, for example, for a facility in which thelocations are clustered into spatially separated areas, and the dataprocessing and storage is done remotely using a client-server model overthe internet.

FIG. 20 shows a self-organizing network in which nearest neighborindicator light devices 251-259 bind with one another. This type ofnetwork organization is suitable, for example, for a facility in whichall locations are clustered together, and only power management andsimple system management functions need to be performed. Network controlmay be thought of as being distributed among the indicator light devices251-259.

Power Management

Although an indicator light device such as the device 20 (FIG. 2) mayhave many power-consuming subsystems, the subsystem having the greatestimpact on the service life of the self-power source is the light.Consider the use of four (4) D-cell alkaline batteries as a self-powersource. Such a battery pack provides about 20,000 mA hours at 4-6 volts.The ultrasonic sensor 28 and the data transceiver 21 may be duty-cycledso that they require relatively little power over the service life ofthe self-power source. If a measurement is taken and communicated in ten(10) second intervals, for example, the sensor 28 and data transceiver21 may be operated so as to draw only about 200 uA, which would allowfor about ten years of battery life. On the other hand, light sourcesconsume much more power. Some LED light sources draw about 100 mW ormore of current at the battery, and even efficient LED light sourcesdraw about 32 mA at the battery. In an “always on” smart parking systemthat uses, for example, efficient 32 mA light sources as indicators, theLED light sources are always on with a particular color to directcustomers to specific available parking spaces. A green light mightindicate “available” while a red light might indicate “occupied,” forexample. Unfortunately, the useable service life of the battery pack inthis 32 mA configuration would be just under one (1) month, which is tooshort to be practical for a smart parking system application. The usableservice life would still be less than adequate even if a more expensivebut longer lived lithium battery power source were used, and even if amore efficient light source were used. Moreover, certain applicationsinvolve the use of indicator lights in sunny locations, where theindicator lights consume even greater power so as to operate withsufficient brightness.

Such networked indicator lights may be operated in a manner that whiledifferent than current approaches, is still entirely satisfactory forthe application even while greatly reducing power consumption.Techniques suitable for greatly extending the service life of the powerpacks in a networked system of indicator lights even while maintainingor enhancing the suitability of the indicator lights for variousapplications include synchronized flashing, specific conditiondetection, relevant time operation, supply-demand based operation,presence operation, and ambient light responsiveness.

FIG. 21 is a schematic diagram illustrating various illustrative powermanagement functions that may be carried out to reduce the powerrequirements of a light source driven by the light driver 300. Flashsynchronizer 270 synchronizes the flashes among the indicator lightdevices within a group, to reduce power consumption while preserving theeffectiveness of the indication to the user. A flash pattern, rate andduty cycle controller 274 controls the flash pattern, rate and dutycycle for such purposes as optimizing visibility and intensity foroptimal visual effectiveness and power savings. Controls 280 whichdeactivate the indicator light devices in certain situations to avoidunnecessary power consumption include condition switch 282, relevanttimes switch 284, supply and demand switch 286, and presence switch 288.Controls 290 which adjust power consumption to optimally balance powerconsumption and performance include relevant times control 292, ambientlight control 294, and manual control 296. Intensity may be controlledin an analog fashion by adjusting the power available to the lightdriver 300, or digitally by adjusting the flash pattern, flash rate,flash duty cycle (as shown in FIG. 21 by phantom lines to the flashpattern, rate and duty cycle controller 274), or any combinationthereof. A sensor 312 is controlled by a sensor control 310.Communications between the controls 270, 282, 284, 286, 288, 292, 294,296 and 310 and other devices, gateways, hosts, clients and servers inthe system are handled by communications 260. These functions and theimplementations described herein may be realized in software, firmwareor hardware, as desired, and may be provided in the devices themselves,or in the gateways, hosts, clients and servers in the system, ordistributed among the devices, gateways, hosts, clients, and servers inthe system in any suitable combination. Where functions are realized insoftware, they may be loaded from or stored in any suitable machinereadable medium, including but not limited to solid state memory such asROM, RAM, SRAM and Flash; magnetic memory, holographic memory, tape,disk, CD ROM, DVD and so forth, whether or not the memory isstand-alone, integrated with a processor core, integrated into a device,available over a network, or otherwise accessible formachine-readability in any way.

Power Management: Flash Pattern, Rate and Duty Cycle Control 274

Current consumption by the light source is greatly reduced by using alow power and efficient light source that is also capable of beingflashed to reduce power consumption further, and then flashing it forthe indication. A light emitting diode (“LED”) is an example of such alight source. By reducing the duty cycle of the LED on-time duringindication, the current consumed can be reduced by the ratio of the dutycycle. For example when the system is flashed for 62.5 ms every 1 sec (1/16th duty cycle), the average current for the indicator reduces toabout 2 mA from its “always on” current of 32 mA. With reference to a20,000 mA hours alkaline battery pack, for example, the service life ofsuch an indicator light may be increased to just over one year. Greaterincreases may be realized by using higher capacity power source such aslithium batteries.

The flash pattern, flash rate, flash duty cycle, and/or analog intensitymay be established at a fixed value optimal or at least satisfactory forthe application, or a default value may be established which may then bevaried based on any desired parameter or parameters. An example of thelatter is to vary the duty cycle for an indicator light at a particularlocation based on the time of day as determined by the relevant timescontrol 292, for example, or the amount of ambient light sensed at ornear that location as determined by the ambient light control 294, forexample, or an observer using manual control 296, for example, or anycombination thereof. The flash pattern, flash rate, flash duty cycle,and/or analog intensity may be determined within an indicator lightdevice based on sensor measurements made by the indicator light deviceand/or based on data and/or commands received from other devices,sensors, gateways, hosts, clients and servers in the system, or may bedetermined within the system but outside of the indicator light deviceand communicated to the indicator light device.

Any desired flash pattern readily visible to the human eye may be used,including simple and complex patterns. An “eye catching” flash patternis particularly suitable. Care should be taken to avoid flash patternsthat can aggravate medical conditions such as seizure. As betweenseveral equally eye catching patterns, the pattern resulting in theleast power consumption is advantageous.

Power Management: Flash Synchronizer 270

The flashing of the indicator lights throughout a particular area oreven through an entire facility may be coordinated to provide a readilyvisible and effective indication to the user without jeopardizing thepower reduction benefits of flashing. Coordinated flashing enables theuser to readily observe at a single glance the indicated status forvarious physical locations in the facility within the user's view.

Flash synchronization may be achieved using synchronization informationconveyed over a wireless network, where the synchronization informationmay be a beacon, a time marker, a flash command, a flash sequencecommand, or any other type of synchronization information. Thesynchronization information may be provided by a synchronizationcontroller, which may be a stand-alone device, part of a device such asa gateway radio, part of a master device, installed in a node or slavedevice, or implemented in a computer such as a host, client or servercomputer. One illustrative technique for flash synchronization is toimplement communications with radios that have time-synchronousoperation, and to use this common capability to trigger the flashing ofthe indicator lights in the network at the same instant. Such radios areavailable from Banner Engineering Corp. of Minneapolis, Minn., USA, andinclude SureCross™ Wireless I/O Products such as the model DX70 and DX80nodes and gateways. The model DX80 radio products, for example,accomplish flash synchronization as follows. A DX80 radio systemincludes a gateway radio and one or more node radios. During run time,the master and slave radios, or gateway and node radios, communicatesynchronously using a sequence of one hundred twenty eight (128)individual time-bounded frames that make up a larger “super frame.”During operation, the master radio sends one or more beacons at thebeginning of one or more frames in the super frame. These beacons areused by the slave radios to establish a common time schedule, so thatall radios know exactly when each frame in the super frame will occurand thereby when they can communicate. In addition, the slave radios mayuse this time schedule to actuate device outputs at precisely definedtimes, thereby enabling synchronized light flash patterns. In set upmode, for example, the DX80 slave radios may be configured with a“recipe” that indicates during which frame(s) the light output(s) shouldbe actuated during run time operation. The recipe may be encoded in abank of eight (8) non-volatile memory registers, each containing asixteen (16) bit word where each bit in the word represents a singleframe in the super frame; If for example all radios are configured witha “recipe” to actuate a light output only during frame one (1) of thesuper frame, the effect will be synchronized flashing of all enabledoutputs with a duty cycle of 1/128. More complicated patterns may becreated as desired by configuring a “recipe” that actuates duringmultiple frames in the super frame.

Another illustrative technique for flash synchronization is fireflysynchronization in ad hoc networks. Various types of fireflysynchronization are well known in the art; see, for example, Tyrrell,Alexander; Auer, Gunther; and Bettstetter, Christian; FireflySynchronization in Ad Hoc Networks, 2006.

Power Management: Condition-of-Interest Switch 282

Where the condition being indicated is presence or absence of something,the indicator light device may be illuminated to indicate only thecondition of interest. In a smart parking system, for example, thecondition-of-interest may be vacant parking spots, or the absence ofparked vehicles. In a pick system, for example, thecondition-of-interest may be the bins where the desired item isavailable, or the presence of the desired items. The indicator lightdevices may be operated to take advantage of the following observation:when trying to find a parking spot or a needed item, a person is onlyinterested in available parking spots or in the bins that contain theneeded item. Therefore the indicator system may be operated to savebattery power by only indicating the desired condition, since the numberof indicator light devices that need to be flashed is often less thanall of the indicator light devices in the system. Illustratively,flashing green LED's may be used to indicate the desired condition“Available” (for example, vacant spots or bins containing a neededitem), while the green LED's would not be illuminated if the desiredcondition were absent (for example, for occupied parking spots or binsthat are empty or contain items that are not needed).

Additional conditions of interest may be indicated by flashing adifferent color light. In a parking system context, for example, filledparking spots, or the presence of parked vehicles, may be indicated byflashing red LED's, and vacant handicapped parking spots, or the absenceof parked vehicles from handicapped parking spots, may be indicated byflashing blue LED's. If desired, each indicator light device may beprovided with colored LED's corresponding to two or more conditions ofinterest, so that each indicator light device may indicate any of theconditions of interest. Alternatively, two or more indicator lightsdevices with respective colored LED's for the respective conditions ofinterest may be located in the same general area to indicate any of theconditions of the conditions of interest. The different colored LED'smay be flashed alternatively or together, as desired.

As a condition of interest indicator, red LED's generally have theparticular advantage of consuming less power than LED's of equalintensity in other colors because the energy gap of the semiconductorefficiently produces a red electroluminescence. Therefore, red LED's maybe used as the only light source in an indicator light device wheremaximize battery life is desired, or may be used as an additional lightsource in an indicator light device to indicate an additional conditionof interest without unduly impacting battery life.

The reduction in indicator on-time achieved by condition-of-interestsensing varies depending on the application, and may be further enhancedby limiting the use of the technique to times when the condition beingsensed is likely to be rare. In smart parking systems, for example,condition-of-interest sensing is particularly effective when used duringbusy times, since relatively fewer parking spots would be available.

Using both flash and condition-of-interest sensing results in over twoyears of operation in the case of the alkaline battery pack example.This calculation is based on a conservative estimate of fifty percentreduction in indicator on-time, which would reduce the average currentfor the indicator to about 1 mA from its “always on” current of 32 mA.Depending on the application and the use of complementary powermanagement techniques to limit condition-of-interest sensing to timeswhen the condition being sensed is likely to be rare, the actualreduction realized may be substantially greater.

Power Management: Relevant Times Switch 284

The indicator system may be operated only during relevant times whenindication is likely to be needed. In the case of a smart parkingsystem, for example, parking guidance may not be needed when thefacility is not busy, which may be inferred with reasonable confidencebased on known “slow” times of the day or hours of closure, or which maybe determined by real time occupancy sensing. When these times arefactored in, the amount of “on-time” of the light of an indicator lightdevice is quite low, even less that 50%.

In the case of a smart parking system, for example, the indicator lightdevices and sensors need to be operated only when the parking facilityis open for business or when the parking facility is likely to be busy.Many parking facilities, for example, are not open for business fortwenty-four hours every day, and may not be busy outside of normalworking or shopping hours except during special events. No parkingindication is needed during these periods. To take advantage of suchsituations, the indicator light device may be operated only during timesthat parking guidance is anticipated to be important. Conservativelyassuming twelve hours per day of sensor and indicator operation andcontinuing the alkaline battery pack example, the average current forthe indicator further decreases to about 0.5 mA from its “always on”current of 32 mA. This provides just over four and a half years ofservice life with the alkaline battery pack. A lithium battery may beused in place of the alkaline battery pack to provide an even longerservice life.

One technique for implementing the relevant times switch 284 is tomaintain a central operation schedule, and communicate appropriateactivate/deactivate commands to the indicator light devices from a hostor a scheduler client. Another technique is to enable each indicatorlight device with a calendar capability, and to preset on/off hours anddays in each indicator light device manually during installation, orover a network after installation during a setup procedure. Anothertechnique is to maintain a central operation schedule and upload theschedule after each update to the indicator light devices, whichactivate and deactivate themselves individually based on the locallystored schedule.

Power Management: Supply/Demand Switch 286

Groups of light indication devices may be selectively activated anddeactivated in stages based on supply and demand of thecondition-of-interest. In the case of a parking garage servicing a mall,for example, the frequency of use of parking spaces tends to declinewith increased distance from the mall entrance. Therefore, during timesof light activity, only the group of indicator light devices nearest themall entrance needs to be activated, while groups of indicator lightdevices increasingly more distant from the mall entrance may besuccessively activated as activity increases. In the case of a warehousepick system, for example, when supply of the desired part is plentifuland available from several locations in the warehouse, only theindicator light device or devices nearest a main aisle or access doorneeds to be activated, while indicator light devices increasingly moredistant from the main aisle or access door may be successively activatedas supplies dwindle. The level of activity may be determined by thesensors associated with the active devices, and the groups of indicatorlight devices may be activated/deactivated based on the number of carsor parts in the facility, or on particular floors or in particular areasof the facility. The supply criteria of parking availability (in thecase of parking garage) or inventory (in the case of a warehouse) may beused to determine whether to enable the indicator light device; forexample, twenty percent full in a section of the facility or the entirefacility. In the case of parking structures, for example, many have somelevel of area counting, such as a level-by-level granularity or asection-by-section granularity, which may be used as a basis forsuccessive activation/deactivation.

In some facilities, light indication may be needed during times of lowactivity only for particular locations within the facility. In the caseof a parking garage servicing a mall, for example, the parking spacesnearest the mall entrance can be expected to be used even during timesof low activity, while the more remote spaces can be expected to bedisused during such times of low activity. In this case, either highcapacity self-powered indicator light devices or line-powered indicatorlight devices may be used for those locations which experience frequentactivity, while self-powered indicator light devices of lower capacityand hence lesser cost may be used for the other locations in thefacility. When activity is low as determined by the sensors monitoringthe near spaces, the remote self-powered indicator light devices may bedeactivated. When activity is high as determined by the sensorsmonitoring the near spaces, the self-powered indicator light devices maybe activated.

One technique for implementing the supply switch 286 is to evaluate datafrom the sensors associated with the indicator light devices on a remotedevice such as a host or client device, and communicate appropriateactivate/deactivate commands to groups of indicator light devices asappropriate. Such data is readily available when the sensors are active.However, for sensors associated with inactive indicator light devices,the inactive devices may be powered up periodically, either by pollingfrom a host or client device, or based on an internal schedule, andtheir results communicated to a host or client for a determination ofwhether the indicator light devices in the area should remain activatedor be deactivated.

Power Management: Presence Switch 288

The sensors used in an indicator system to detect the status of thelocations may be supplemented by additional sensors for user presencedetection. Supplemental sensors may be used, for example, to detect thepresence of a user requiring an indication, so that indicator lightdevices may remain deactivated unless a user is present. In the case ofa smart parking system, for example, indicator light devices and theirassociated sensors within a particular area may be activated when avehicle is present in the vicinity. A supplemental sensor such as awireless magnetometer may be used to detect the general presence ofvehicles. When a vehicle is detected, the indicator light devices andtheir associated sensors in the area are activated. If no furtheractivity is detected by the magnetometer or by the sensors for the areawithin a period of time, illustratively a fixed amount of time such assixty seconds, the indicator light devices and their associated sensorsin the area may be deactivated. The magnetometer remains active so thatif another vehicle is detected by the magnetometer before the timeelapses, the time is extended until the algorithm times out. In this waythe sensor-indicator devices within an area are operated only when avehicle is trying to find a spot in that area.

Other suitable types of user presence sensors include photoelectricbeams, card readers, video monitors, attendant observation, and soforth.

Power Management: Relevant Times Control 292

The indicator system may be operated at greater or lesser intensitydepending on relevant times. Light brightness may be varied based ontime of day, for example. In the case of a smart parking system, forexample, the indicator light devices may be operated at lesser intensityin early morning or late evening. In parking structures having areasthat are shaded during certain times of day, the indicator light devicesmay be operated at lesser intensity at these times.

One technique for implementing the relevant times control 292 is tomaintain a central operation schedule on a host or a scheduler client,and communicate appropriate activate/deactivate commands to theindicator light devices from the host or the scheduler client. Anothertechnique is to enable each indicator light device with an internal dateand time clock, and to preset on/off hours and days in each indicatorlight device manually during installation, or over a network afterinstallation during a setup procedure. Another technique is to maintaina central operation schedule and upload the schedule after each updateto the indicator light devices, which activate and deactivate themselvesindividually based on the locally stored schedule. The intensity ofoperation may be controlled digitally by adjusting the flash rate and/orduty cycle, or in an analog manner by adjusting the current available tothe light source, or by a combination thereof. Operation of the relevanttimes control 292 and the relevant times switch 286 may be combined ifdesired.

Power Management: Ambient Light Control 294

An ambient light detector may be used to detect the amount of ambientlight about an indicator light device, so that intensity of the lightmay be adjusted to the lowest amount necessary to operate the light atsufficient intensity for the local ambient conditions. Smart parkingsystems often are used in parking structures which are generally darkmost times of the day so the light currents can be quite low on average.However during sunny times of day, certain spots such as the ends ofrows may be more brightly illuminated due to their location within theparking facility. Moreover, even a parking structure may have parkingspots exposed to the outside. An ambient light detector may be includedin the vicinity of several indicator light devices or with eachindicator light device (for example, in the housing of a device whichcombines the sensor and indicator, or in the housing of the indicatorwhere the sensor and indicator are separately housed) so that based onthe amount of light detected at a particular spot, the light intensitymay be increased or decreased to provide sufficient illumination for theindication with minimum effective power consumption. The ambient lightmeasurement may be made in the dead time between flashes to avoid being“sprayed” by the LED indicator; this results in a more accurate ambientlight measurement.

One technique for implementing the ambient light control 294 is tomaintain data on the ambient light conditions and perform the ambientlight control calculations centrally, on a host or client, andcommunicate appropriate flash pattern, rate, duty cycle, and/or currentadjustment commands to the indicator light devices. Another techniquethat is suitable particularly when an indicator light is provided withits own ambient light sensor is for the indicator light device to adjustits own intensity directly, based on the output of the ambient lightsensor.

Power Management: Manual Control 296

Manual control of light intensity may be provided if desired. Manualcontrol may be provided to allow full override of all functions or ofonly selected functions.

Device Implementation Example

FIG. 22 is a plan view of an implementation of the wirelessly networkedindicator light device 200 of FIG. 2 in the form of a unitary deviceassembled from interconnected modules. A battery module 320illustratively containing four (4) D-cell alkaline batteries or lithiumbatteries serves as the base of the device, and is used to mount thedevice to any suitable surface from the bottom or side surfaces of thebattery module 320. A battery module cover 322 completes the batterymodule 320. A data radio module 330 and a light and sensor module 340are mounted to the battery module cover 322 in any suitable manner,illustratively by respective externally threaded conduits which projectfrom the data radio module 330 and the light and sensor module 340through respective holes in the battery module cover 322 and are securedby respective nuts. The light and sensor module 340 includes an embeddedultrasonic sensor 344 for emitting ultrasonic waves 346 and detectingreflected waves (not shown), and a transparent or translucentsemispherical housing section for emitting light 342 of a desired coloror colors. The data radio module 330 includes a data transceiver (notshown), an embedded antenna (not shown), and a button 332 which aninstaller may press to bind the data radio module 330 to a suitablewireless network. Alternatively, the ultrasonic sensor 344 may be usedfor this purpose by implementing a distance-sensing function. If theultrasonic sensor detects an object within a small distance of thesensor face for a certain amount of time, such as the installer's handpositioned near the sensor face, the indicator light device then entersinto binding mode for a certain amount of time. The size andconfiguration of the battery module 320, the data radio module 330, andthe light and sensor module 340, and the type of interconnectiondescribed are illustrative, and a variety of different sizes,configurations and interconnection techniques are suitable.

FIG. 23 is a plan view of an implementation of the wirelessly networkedindicator light device 200 of FIG. 2 in the form of a unitary device. Abattery and circuit compartment 350 illustratively contains four (4)D-cell alkaline batteries or lithium batteries and the circuit board orboards for the device electronics, including processor, memory, radioand antenna, serves as the base of the device, and is used to mount thedevice to any suitable surface from the bottom or side surfaces of thebattery compartment 350. A compartment cover 352 completes thecompartment 350. A light and sensor housing 360 is mounted to thebattery module cover 352 in any suitable manner, illustratively by anexternally threaded conduit which projects from the light and sensormodule 360 and through a hole in the cover 352 and secured by a nut. Thelight and sensor housing 360 includes an embedded ultrasonic sensor 364for emitting ultrasonic waves 366 and detecting reflected waves (notshown), and a transparent or translucent semispherical housing sectionfor emitting light 362 of a desired color or colors. A binding button(not shown) may be provided on the side of the compartment 350 or insidethe compartment 350, so that an installer may press the button to bindthe data radio to a suitable wireless network. Alternatively, theultrasonic sensor 364 may be used for this purpose by implementing adistance-sensing function. If the ultrasonic sensor detects an objectwithin a small distance of the sensor face for a certain amount of time,such as the installer's hand positioned near the sensor face, theindicator light device then enters into binding mode for a certainamount of time. The size and configuration of the indicator light deviceshown in FIG. 23 are illustrative, and a variety of different sizes,configurations and interconnection techniques are suitable.

FIG. 24 is a schematic diagram of a circuit 400 suitable for thewirelessly networked indicator light device implementations shown inFIG. 22 and FIG. 23. The various functions of the circuit 400 arecontrolled by a suitably programmed programmable controller 420.Wireless networking is handled by RF module 410, in accordance withvarious signals PATTERN, DATA_IN, DATA, DATA.CLK, DATA.OUT, ENABLE andSWCH between the RF module 410 and the controller 420. Wired networkingis handled by RS485 circuit 430, in accordance with various signalsRX_485, TX_485, RE_485 and DE_485 between the RS485 circuit 430 and thecontroller 420. External control signals may be applied through sinkinginputs 440 and 450. An ultrasonic transducer 512 is driven by sensorinterface 510, with transducer drive being controlled by signalsU_DRIVE1 and U_DRIVE2 between the controller 420 and the sensorinterface 520. Object proximity is detected by comparator 500, and thedetection results are reported by signal U_COMP between the comparator510 and the controller 420. Light output may be red, green or blue. Thepulse rate and duty cycle of red light output from an array of LEDelements 521, 522, 523 and 524 is controlled by signals OUTP1 from thecontroller 420 to driver 520. The pulse rate and duty cycle of greenlight output from an array of LED elements 531, 532, 533 and 534 iscontrolled by signals OUTP2 from the controller 420 to driver 530. Thepulse rate and duty cycle of blue light output from an array of LEDelements 541, 542, 543 and 544 is controlled by signals OUTP3 from thecontroller 420 to driver 540. and to VBOOST circuit 550 respectively.While pulse width modulation is an efficient way to control pulseintensity, pulse intensity may also be controlled by analogue withelectronically adjustable set current resistor 551.

Power to the various components of the circuit 400 is provided byregulator 470, while power to the RF module 410 is provided by RFregulator 480. The power source may be external line power VCC in therange of from twelve to twenty-four volts, which is pre-regulated bypre-regulator 460 before being applied to the regulator 470 and the RFregulator 480, or may be battery power in the range of three to fivevolts applied to the regulator 470 and the RF regulator 480. The highervoltage VBOOST required for the LED drivers 520, 530 and 540 isgenerated in the VBOOST circuit 550 using, for example, a switch modeconverter.

The battery pack providing VT may be capacitor-backed to maintain a lowpeak current. Batteries generally, and alkaline batteries in particular,have a higher capacity at lower average current. However, when the LED'sare flashed, the current drawn from the battery can approach 100 mA withsome less efficient LED's. To avoid this high peak current drain, thebatteries may be backed by a sufficiently large capacitive device, orsuper capacitor, to ensure that the peak current from the battery staysnear the average operating current, illustratively less than about 5 mA.This technique further improves battery capacity; at low temperaturesthis improvement may be considerable.

A variety of indicator lights, sensors, and wireless system componentssuitable for a variety of applications including smart parking systemsgenerally and pick systems generally are available from BannerEngineering Corp. of Minneapolis, Minn., USA; see, e.g., Products &Applications: Indicator Lights, downloaded fromhttp://www.bannerengineering.com/en-US/product on Sep. 21, 2010.

Application Example: Parking Garage

FIG. 25 shows an illustrative system for wireless vehicle detection andindication to be used in single space parking and way findingapplications. The solution utilizes a combination of wirelessconnectivity, ultrasonic sensors, magnetometers, and/or battery power tocreate a parking sensor system that is effective over a long servicelife, while being inexpensive, convenient and easy to install andmaintain.

The system uses a hierarchical wireless sensor and indicator networkinstalled throughout a parking garage. The individual components includewireless ultrasonic sensor and LED indicator nodes, wirelessmagnetometer nodes, wireless ultrasonic sensor nodes, wireless LEDindicator nodes, battery packs, wireless gateway devices, and a host.

The parking garage illustrative has four ramps or levels 600, 610, 620and 630. The top or fourth level ramp 600 is open to the sky andprovides three parking spaces 604, 606 and 608, all of which areoccupied by vehicles. Magnetometers 605, 607 and 609 located on the ramp600 are used to detect vehicles parked over them, and are powered withintegrated D-cell lithium batteries to achieve a long service life.Suitable magnetometers include the model M-Gage™ DX80 node availablefrom Banner Engineering Corp. of Minneapolis, Minn., USA. Whilemagnetometers 605, 607 and 609 are shown as cylindrical devices mountedinto respective holes in the ramp 600, they may take the form of a halfoblate spheroid that is surface-mounted, or any other desired form.Indicator lights are not used, but may be used if desired. If used, theymay be pole-mounted, wall-mounted or floor-mounted, and may be operatedat a high intensity to be readily visible to drivers. The magnetometers605, 607 and 609 are provided with wireless communications capabilityand are wirelessly networked to wireless gateway 602, which is wired toa data radio 601 for communications to a host computer 640 via dataradio 631.

The third level ramp 610 is covered by a ceiling and provides threeparking spaces 614, 616 and 618, of which space 614 is vacant and spaces616 and 618 are occupied by vehicles. Respective indicator-sensordevices 615, 617 and 619 are mounted on a ceiling over ramp 610 and arepositioned over the parking spaces 614, 616 and 618. Each of the devices615, 617 and 619 is a unitary device similar to the wirelessly networkedindicator light device shown in FIG. 23, and contains an indicatorlight, an ultrasonic sensor, wireless communications and controlcircuitry, and a self-power source. In this example, it is presumed thatsensing, indication and wireless communication may all be effectivelyperformed from the same position over the parking spaces of the thirdlevel ramp 610. The self-power source may be D-cell lithium batteries toachieve a long service life, or may be four (4) D-cell alkalinebatteries if the anticipated power consumption is low or if long servicelife is not needed. Alternatively, if line voltage is available, it maybe used instead of the self-power source. The devices 615, 617 and 619are wirelessly networked to wireless gateway 612, which is wired to adata radio 611 for communications to the host computer 640 via the dataradio 631.

The second level ramp 620 is covered by a ceiling and provides threeparking spaces 624, 626 and 628, all of which are occupied by vehicles.Respective indicator-sensor devices 625, 627 and 629 are mounted on aceiling over ramp 620 and are positioned over the parking spaces 624,626 and 628. Each of the devices 625, 627 and 629 is made of modulessimilar to the wirelessly networked indicator light device shown in FIG.22, and contains an indicator light module (see module 644 of the device639), an ultrasonic sensor module (see module 642 of the device 639), awireless communications and control circuitry module (see module 641 ofthe device 639), and a self-power source module (see module 643 of thedevice 639). However, unlike the device shown in FIG. 22, only theultrasonic sensor module and the wireless communications and controlcircuitry module are assembled into a unit, which is interconnected tothe indicator light module and the self-power source module by suitablewiring. In this example, it is presumed that sensing and wirelesscommunication may be effectively performed from the same position overthe parking spaces of the second level ramp 620, but that indication andmounting of the power supply are preferably performed at differentlocations. The self-power source may be D-cell lithium batteries, D-cellalkaline batteries, or line voltage, as desired. The devices 625, 627and 629 are wirelessly networked to wireless gateway 622, which is wiredto a data radio 621 for communications to the host computer 640 via thedata radio 631.

The first or ground level ramp 630 is covered by a ceiling and providesthree parking spaces 634, 636 and 638, all of which are occupied byvehicles. Respective indicator-sensor devices 635, 637 and 639 aremounted on a ceiling over ramp 630 and are positioned over the parkingspaces 634, 636 and 638. Each of the devices 635, 637 and 639 is made ofmodules, and is similar to each of the devices 625, 627 and 629. In thisexample, it is presumed that sensing and wireless communication may beeffectively performed from the same position over the parking spaces ofthe first level ramp 630, but that indication and mounting of the powersupply are preferably performed at different locations. The devices 635,637 and 639 are wirelessly networked to wireless gateway 632, which iswired to the host computer 640.

The hierarchical network architecture used in the parking system of FIG.25 is scalable. The sensor network is partitioned into multiplesub-nets, each of which may have any number of sensor nodes and onewireless gateway. The sensor nodes are addressed in any desired mannersuch as, for example, with rotary switches, and are bound to aparticular gateway during operation.

The gateways are represented in the network as Modbus slaves. Eachgateway is given a different Modbus slave address. The sensor nodeoccupancy data for an entire sub-net is held in a bitwise representationusing, for example, an efficient coding such as 7 bytes which containthe status of all nodes.

The host controller is configured as a Modbus Master device. Occupancyat the parking facility may be captured by periodically polling thebitwise occupancy registers in the respective gateways for the sub-nets.Configuration and diagnostic information may be obtained by pollingindividual holding registers.

Advantageously, the system is scalable. In the illustrative systemdescribed, a single host controller, or Modbus master, can oversee 247different gateway sub-nets. Each sub-net can contain up to 56 sensornodes. Therefore the total occupancy per master is 13,832 sensor nodes.These capacities are illustrative, since many other systems andcapacities are available.

Suitable network components and wireless magnetometer nodes areavailable from Banner Engineering Corp. of Minneapolis, Minn., USA.

Application Example: Parking Facility with Dynamically Assigned ParkingSpaces

Indicator light devices may be used in a system for dynamicallyassigning and reserving parking spaces for specific users, especially infacilities for which demand for parking spaces may exceed supply. Anillustrative system of this type includes devices at points of ingressand egress for associating the vehicle or occupant with a unique code,such as, for example, a keypad for receiving a code pre-assigned to anoccupant of the vehicle, a reader for reading an electronic room key orother type of key card, a bar code reader for reading a bar code appliedto the vehicle or carried by an occupant, an NFC reader for reading acode from an NFC transmitter applied to the vehicle or presented by anoccupant, a license plate reader, and so forth. In a hotel parkinggarage, for example, the reception clerk may provide the code to a guestduring check-in.

The code is acquired by the system as the vehicle occupied by the guestapproaches the facility. In the hotel example, a keypad may be providedat the entrance to the parking garage so that that guest may key in thecode, or a key card reader may be provided to read the encoding on theguest's electronic room key, wherein the encoding may serve as the code.The system authenticates the code and allows the vehicle to enter theparking facility. As part of the authentication process, the receptionclerk may during the check-in process set a guest status parameterassociated with the code in the system as “unassigned” so that personswho have not checked in or who have checked out (the guest status may becleared at check-out) may be denied access to the parking garage.

The system assigns a parking space to the vehicle. One technique is forthe system to pre-assign the parking space. In the hotel example, thesystem may automatically select a parking space number, change the gueststatus parameter to the assigned parking space number, and flash theindicator light device associated with the assigned parking space asuggestive color, illustratively green. All other indicator lightdevices in the system may be left dark or flashed red. Another techniqueis to allow the driver to select any available parking space. The systemmay flash all available spaces a suggestive color such as green, whilethe unavailable spaces may be flashed another suggestive color such asred. When the driver parks the vehicle in one of the available parkingspaces, the vehicle is detected and the system may change the gueststatus parameter to the assigned parking space number. In either case,the indicator lights may be turned off after the vehicle is detected inthe parking space to manage power consumption. Another technique is forthe reception clerk to manually instruct the system to assign aparticular available parking space to the vehicle.

The vehicle may leave the parking facility without losing parkingprivileges. When a legally parked vehicle egresses the parking facilityand attempts to re-enter, the system acquires and authenticates the codeas the vehicle approaches the facility, and allows the vehicle to enterthe parking facility. In one technique, the system flashes the indicatorlight device associated with the assigned parking space a suggestivecolor, illustratively green, based on the code. All other indicatorlight devices in the system may be left dark or flashed red. Anothertechnique is for the system to change the guest status parameter to“unassigned” upon re-entry, and allow the driver to select any availableparking space as described above. Note that the parking space remainsassigned while the vehicle is away, thereby preserving parkingprivileges. In either case, the indicator lights may be turned off afterthe vehicle is detected in the assigned parking space.

The system may have various additional capabilities. A notablecapability for facilities in which demand may exceed supply includesreporting facility capacity, and in particular a facility full alert sothat alternative parking arrangements may be initiated when the parkingfacility is full.

The system may be provided with additional capabilities for detectingfraudulent or mistaken parking activity so that corrective action may betaken, either by the system or by a facility agent such as, in the hotelexample, by the reception clerk, concierge, or parking attendant. Onetype of mistake is for an authenticated vehicle to park in a “wrong”parking space, such as a space that is not assigned to it. If the wrongparking space is assigned to another, the system may flash the indicatorlight device associated with the wrong parking space a suggestive color,illustratively yellow, and generate an “investigate” alert so that theproblem may be promptly resolved by a facility agent. If the space isunassigned, the parking attempt may be treated as a space assigned toanother, or may be treated as a new parking space assignment asdescribed above.

Another type of mistaken parking activity is the slow parker. If thefirst-to-enter vehicle is confused or slow to park, a second vehicle mayenter the parking facility before the first-to-enter vehicle has parked.If parking spaces are assigned to both vehicles and the system isconfigured for returning vehicles to park in previously assigned spaces,a problem may occur either when the first-to-enter vehicle parks in theparking space assigned to the second-to-enter vehicle, or when thesecond-to-enter vehicle parks in the parking space assigned to thefirst-to-enter vehicle. One technique for handling this problem is toautomatically reassign the parking spaces. Another technique is to takeno action. If one of the vehicles should leave and return, it may not beable to park in its previously assigned space and would then be treatedas a parking in a wrong space. Another technique for handling thisproblem is to presume that the problem arises whenever a second vehicleenters before a first-to-enter vehicle has parked, in which case thesystem may flash the indicator light devices associated with bothassigned parking spaces a suggestive color, illustratively yellow, andgenerating an “investigate” alert to a facility agent.

A common and serious problem with some parking facilities is the illegalvehicle that closely follows an authorized vehicle into the parkinggarage through the entrance gate. Should the system detect one or moreadditional parkings during the interval between two code acquisitions,the system may flash the indicator light devices associated with all ofthe parking spaces occupied during that interval a suggestive color,illustratively yellow, and generate an “investigate” alert to a facilityagent.

Another common and serious problem with some parking facilities is theillegal vehicle that uses a code assigned to another. If the codesubmitted by an arriving vehicle is authenticated but the assigned spaceis occupied, the parked vehicle in the assigned space could be either alegal occupant or an illegal occupant. While the system may prohibitentry to the arriving vehicle, this may not be desirable since thearriving vehicle may be a legal occupant. Therefore, the system mayallow the arriving vehicle to enter but indicate available spaces byflashing the associated indicator light devices a suggestive color,illustratively yellow. When the arriving vehicle is parked, the systemmay flash the indicator light devices associated with the spacescontaining the arriving vehicle and the parked vehicle a suggestivecolor, illustratively yellow, and generate an “investigate” alert to afacility agent.

An “investigate” alert may be handled in any desired manner.Illustratively, the investigate alert may be provided to the facilityagent, who upon receiving may inspect the vehicles parked in spotsindicated by yellow lights, query the system for the room numbers of theguests associated with the parking spaces (or this information may beprovided as part of the “investigate” alert), contact the guests tounderstand the situation, instruct the system to make any desirablereassignments, and take appropriate enforcement action against illegallyparked vehicles.

The description of the various embodiments of the invention includingits applications and advantages as set forth herein is illustrative andis not intended to limit the scope of the invention. Variations andmodifications of the embodiments disclosed herein may be made, andpractical alternatives to and equivalents of the various elements of theembodiments would be known to one of ordinary skill in the art upon astudy of this patent document. Moreover, unless otherwise stated anyvalues provided herein are approximations and are illustrative, as wouldbe appreciated by one of ordinary skill in the art. These and othervariations and modifications of the embodiments disclosed herein,including of the alternatives and equivalents of the various elements ofthe embodiments, may be made without departing from the scope and spiritof the invention as set forth in the accompanying claims.

The invention claimed is:
 1. A system with energy management of visualcapacity indicators for a facility, the system comprising: a controller;a plurality of indicator light devices (ILDs), wherein each ILD of theplurality of ILDs is connected via a network to the controller, each ILDof the plurality of ILDs is associated with a physical location and isconfigured to activate or deactivate a light source associated with eachof the physical locations, and each ILD is coupled to at least onepresence detector, wherein, for each of the ILDs in the plurality ofILDs, the corresponding at least one presence detector is configured todetect whether each of the physical locations associated with the ILD isoccupied; a counting module operably coupled to the controller andconfigured to monitor an available supply of unoccupied physicallocations in the plurality of physical locations; a non-transitorycomputer-readable medium operably coupled to the controller, wherein thecomputer-readable medium comprises a program of instructions that, whenexecuted by the controller, cause the controller to perform operationsto conserve power for the ILDs, the operations comprising: receive anavailable supply signal from the counting module, the available supplysignal representing the available supply of unoccupied physicallocations in the plurality of physical locations; determine, based onthe received available supply signal, whether a percentage of all of thephysical locations that are occupied meets a predetermined occupancythreshold; receive a presence signal from each of the presence detectorscoupled to each of the ILDs in the plurality of ILDs, the receivedpresence signals identifying which of the physical locations isoccupied; if the percentage of all of the physical locations that areoccupied meets the predetermined occupancy threshold, selectivelyactivate, for each ILD of the plurality of ILDs, the light sourceassociated with each of the physical locations that is not occupied;and, if the percentage of all of the physical locations that areoccupied does not meet the predetermined occupancy threshold, deactivateall of the light sources of all the ILDs in the plurality of ILDs. 2.The system of claim 1, wherein the each of the physical locationscomprises at least one parking space of a parking facility.
 3. Thesystem of claim 1, wherein each of the ILDs in the plurality of ILDs isoperably coupled to at least one sound source indicator.
 4. The systemof claim 1, further comprising a clock module operably coupled to thecontroller and configured to determine, based on the received availablesupply signal, a slow time of the day during which the percentage of allof the physical locations that are occupied is not likely to meet thepredetermined occupancy threshold, and to deactivate the at least onelight source of each ILD of the plurality of ILDs during the determinedslow time of the day.
 5. The system of claim 1, wherein each ILD of theplurality of ILDs further comprises a network module in operablecommunication with the controller.
 6. The system of claim 1, wherein thenetwork comprises a wireless network.
 7. The system of claim 1, whereinthe operation to activate the light source of each ILD of the pluralityof ILDs further comprises synchronously flashing at least one of thelight sources that is associated with one of the physical locations thatis not occupied.
 8. The system of claim 1, wherein the operation toactivate the light source of each ILD of the plurality of ILDs furthercomprises coordinating flash patterns for at least one light source thatis associated with one of the physical locations that is not occupied.9. The system of claim 1, wherein the operations further comprise todetermine, based on the received presence signal, whether a percentageof all of the physical locations that are occupied meets a predeterminedoccupancy threshold.
 10. The system of claim 1, further comprising aself-powered source coupled to each ILD of the plurality of ILDs. 11.The system of claim 1, wherein each of the presence detectors isselected from the group consisting of: a magnetometer, an ultrasonicsensor, and a camera.
 12. A system with energy management of visualcapacity indicators for a facility, the system comprising: a controller;a plurality of indicator light devices (ILDs), wherein each ILD of theplurality of ILDs is connected via a network to the controller, each ILDof the plurality of ILDs is associated with a physical location and isconfigured to activate or deactivate a light source associated with eachof the physical locations, and each ILD is coupled to at least onepresence detector, wherein, for each of the ILDs in the plurality ofILDs, the corresponding at least one presence detector is configured todetect whether each of the physical locations associated with the ILD isoccupied; a non-transitory computer-readable medium operably coupled tothe controller, wherein the computer-readable medium comprises a programof instructions that, when executed by the controller, cause thecontroller to perform operations to conserve power for the ILDs, theoperations comprising: determine whether a percentage of all of thephysical locations that are occupied meets a predetermined occupancythreshold; if the percentage of all of the physical locations that areoccupied meets the predetermined occupancy threshold, selectivelyactivate, for each ILD of the plurality of ILDs, the light sourceassociated with each of the physical locations that is not occupied;and, if the percentage of all of the physical locations that areoccupied does not meet the predetermined occupancy threshold, deactivateall of the light sources of all the ILDs in the plurality of ILDs. 13.The system of claim 12, wherein the each of the physical locationscomprises at least one parking space of a parking facility.
 14. Thesystem of claim 12, wherein each ILD of the plurality of ILDs furthercomprises a network module in operable communication with thecontroller.
 15. The system of claim 12, wherein the network comprises awireless network.
 16. The system of claim 12, wherein the operation toactivate the light source of each ILD of the plurality of ILDs furthercomprises synchronously flashing at least one of the light sources thatis associated with one of the physical locations that is not occupied.17. The system of claim 12, wherein the operation to activate the lightsource of each ILD of the plurality of ILDs further comprisescoordinating flash patterns for each of the light sources that isassociated with one of the physical locations that is not occupied. 18.The system of claim 12, further comprising a self-powered source coupledto each ILD of the plurality of ILDs.
 19. The system of claim 12,wherein the operations further comprise: receive a signal from each ofthe presence detectors coupled to each of the ILDs in the plurality ofILDs, the received signals identifying which of the physical locationsis occupied.
 20. The system of claim 19, wherein the operation todetermine whether a percentage of all of the physical locations that areoccupied meets a predetermined occupancy threshold is further based onthe received signals.
 21. A system with energy management of visualcapacity indicators for a facility, the system comprising: a controller;a plurality of indicator light devices (ILDs), wherein each ILD of theplurality of ILDs is connected via a network to the controller, each ILDof the plurality of ILDs is associated with a physical location and isconfigured to activate or deactivate a light source associated with eachof the physical locations, and each ILD is coupled to at least onepresence detector, wherein, for each of the ILDs in the plurality ofILDs, the corresponding at least one presence detector is configured todetect whether each of the physical locations associated with the ILD isoccupied; a clock module operably coupled to the controller andconfigured to monitor operable times of the day; a non-transitorycomputer-readable medium operably coupled to the controller, wherein thecomputer-readable medium comprises a program of instructions that, whenexecuted by the controller, cause the controller to perform operationsto conserve power for the ILDs, the operations comprising: determine anoperable time of the day in accordance with a predetermined operatingtime, during the determined operable time of day: determine whether apercentage of all of the physical locations that are occupied meets apredetermined occupancy threshold; if the percentage of all of thephysical locations that are occupied meets the predetermined occupancythreshold, selectively activate, for each ILD of the plurality of ILDs,the light source associated with each of the physical locations that isnot occupied; and, if the percentage of all of the physical locationsthat are occupied does not meet the predetermined occupancy threshold,deactivate all of the light sources of all the ILDs in the plurality ofILDs; and, outside of the determined operable time of day: deactivateall of the light sources of each ILD of the plurality of ILDs until anoperable time is determined.